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Morrisons Awarded Patent Entitled, "Method of Estimating Pulse Response Using an Impedance Spectrum"


Dr. John Morrison, Professor in the Electrical Engineering Department at Montana Tech, and Mr. Bill Morrison, Research Engineering in the Montana Tech Electrical Engineering Department, were recently awarded a patent entitled, “Method of estimating pulse response using an impedance spectrum,” US Patent 8868363. Electrochemical Impedance Spectrum data are used to predict performance of an energy storage device such as a battery. Dr. Morrison’s patent allows for the spectrum to be calculated in-situ. Co-authors on the patent include Dr. Jon Christophersen and Mr. Chester Motloch, both of Idaho Falls.

A summary of the patent follows:
A simulation waveform includes a pulse wave with a period greater than or equal to the lowest frequency used in the impedance measurement. Fourier series coefficients of the pulse train can be obtained. The number of harmonic constituents in the Fourier series are selected so as to appropriately resolve the response, but the maximum frequency should be less than or equal to the highest frequency used in the impedance measurement. Using a current pulse as an example, the Fourier coefficients of the pulse are multiplied by the impedance spectrum at corresponding frequencies to obtain Fourier coefficients of the voltage response to the desired pulse. The Fourier coefficients of the response are then summed and reassembled to obtain the overall time domain estimate of the voltage using the Fourier series analysis.

For more information, please contact Dr. Morrison at 406-496-4515.